Generally, a semiconductor die may be connected to other devices external to the semiconductor die through a type of packaging utilizing solder bumps. The solder bumps may be formed by initially forming a layer of under bump metallization in contact with a conductive portion of the semiconductor die and then placing a conductive feature and solder onto the under bump metallization. A reflow operation may then be performed in order to shape the solder into the desired shape. The solder may then be placed into physical contact with the external device and another reflow operation may be performed in order to bond the solder with the external device. In such a fashion, a physical and electrical connection may be made between the semiconductor die and an external device, such as a printed circuit board, another semiconductor die, or the like.
Different materials, such as dielectric materials, metallization materials, etch stop materials, barrier layer materials, and other materials utilized in the formation of the semiconductor die may each have a unique coefficient of thermal expansion that is different from the other materials. This type of coefficient of thermal expansion mismatch causes each one of the materials to expand differently when the semiconductor die is heated during later processing, testing or use. As such, at elevated temperatures there is a coefficient of thermal expansion mismatch that causes stresses to form between the different materials and, hence, the different parts of the semiconductor die. These stresses can cause delamination to occur between the various layers of material. This delamination can damage the semiconductor die during the manufacturing process or else during its intended use.